This invention relates to an anti-cancer agent and process for preparing same. More particularly, this invention relates to an agent obtained from human serum which inhibits and/or prevents the growth of tumor cells.
The presence of an anti-tumor factor (TNF, tumor necrosis factor) in the serum of animals has been described in Cancer Letters, 6: 235-240 (1979).
Following the injection of bacterial endotoxin, TNF is found in the serum of mice inoculated with Corynebacterium parvum (CP). TNF was purified about 50 fold and is believed to be a .alpha..sub.2 globulin having a molecular weight of about 150,000. TNF was detected by an in vitro assay using mouse L-cells and by an in vivo bioassay, using female BALB/c mice bearing a methyl cholanthrene-induced fibrosarcoma.
TNF-like activity has been found in extracts of liver microsomes from CP-treated mice and in very low, but measurable amounts in microsomes from livers of normal mice. TNF has also been found in the serum of normal mice.
A fraction of the .alpha..sub.1 - .alpha..sub.2 globulins from serum of normal humans has been found to be cytotoxic for mouse L cells in culture and Meth A tumors in mice (Cancer Letters, 6: 235-240 1979) and inhibited the growth, in vitro, of human colon cancer, melanoma and neuroblastoma cells lines (J. Cell. Biol., 79: 67, 1978).